If you decide to pull the trigger on this, I would urge to to get the 200gb hard drive as it runs at 7200 rpm. The 250gb runs at 5400 rpm. That's the config I have on order (he waits patiently...). I wanted the extra storage but the performance is more important to me so I got a 320gb external firewire 400/800 from OWC. Speaking of which I'll throw out a question:

I also ordered a 2gb memory stick from OWC. I think my MBP comes with 2 1gb memory sticks- one in each of the 2 slots. If I don't buy another 2gb stick and leave one of the 1gb sticks in place for a total of 3gb, will that affect performance as they will not be a matched pair? If it doesn't affect performance, I think 3gb should be enough for all of the games out there but I'll appreciate feedback on that as well.

It will affect performance, but unless you do a lot of RAM intensive stuff, you probably won't notice it.
7200rpm vs 5400rpm harddisks is, in my opinion a waste of money.
Even at 7200rpm, a notebook harddisk will be too slow to allow for some of the more serious data juggling, like video editing etc.
But it will be much louder, hotter and consume a lot more power, draining battery life.
The bigger, but slower 5400rpm drive however will offer more space. Seeing how my 160GB drive is already 90% full, I'd go for more storage space on a laptop any time. Exchanging the harddrive in an MBP is considerably more work than attaching a fast firewire 800 or eSata harddrive externally. And the later will neither drain your battery, nor be too slow to do the job you want it to do.
If I was to buy a MBP now, I'd take the 2.6GHz 15" with 250GB 5400rpm disk for maximum lifespan.